So last week I asked for help as my first built PC was turning off randomly before or after POST, or in the middle of Vista, basically anytime. Answers pointed to RAM or PSU. I run Vista 32-bit and had put 4GB of RAM, so I started by taking out a 2GB bar, and I thought that had solved it. But after 5 days of stability, it started shutting down again. I just replaced the original 500W PSU with a 650W one, but same thing. I replaced my OCZ DDR2 PC6400 2GB RAM with 2x1GB, same problem. So it's not the RAM nor the PSU. It's not overheating as it happens first thing on a fresh boot on a cold CPU.

What is disturbing is that it occasionally happens before Vista is loaded, during POST, after I get the OK beep, it just shuts off and tries to restart, and same thing. I have to turn off power to stop it trying in 15 second cycles. This would point to a hardware problem (or Bios?). When I first installed Vista, it would not complete the install and I had to reflash the Bios from a flash drive from the latest I found on the Asus site.

If I let it rest for a few hours (and if I’m lucky), it will start again, boot Vista, work for an hour or a day, then shut down clean, i.e. it logs off, and if I’m recording in Media Center, it warns me that shutting off will stop recording. If I say no, then it doesn’t and asks again 2 mins later. At that point I think it’s a software problem, and suspect Norton Security suite or a Crysis demo which I installed yesterday after 5 days of stability. I thought it was safe to get into the water again…

I would really appreciate help to further diag this please. I'm 4 weeks into this ;-( and this is my first build, which is turning into a bit of a nightmare.

Mobo Asus P5E -VM-HDMI reflashed - CPU Intel Q6600 - WINTV HVR 1800 - ABIT Airpace Wifi - E-GeForce 8400 GS – 2x1GB Patriot PC6400 DDR2 – APEVIA QPack2 with 500W PSU

This PC is mainly for HTPC purposes hence the dual tuner, some MP4 HD video edition, and Gears of War occasionally (which I had trouble installing, but now works after I loaded the Live Games Redistributable from MS). But so far it is mainly for late nights and no joy.

Sounds frustrating for sure! If it were me, I would try swapping my harddrive incase it was corrupted, but other than that it sounds like one of your components is just not working properly, possibly the motherboard, but I really coudn't say for sure. You may want to talk to the retailer and ask them if you can RMA your mobo or CPU or something because this just is unacceptable.

Best of luck.

Unfortunately, Apevia makes poor quality PSU's. You did not mention what brand the 650w was, but more watts does not equal better quality.

I am also unaware of either Patriot or OCZ being on the approved list for ASUS. As a rule, I generally avoid Patriot anyway. I tend to stick with name brands like Crucial and Corsair.

If you have not already seen it, this guide may be of assistance. http://www.tomswiki.com/page/Troub [...] ild?t=anon

I had a friend who's machine was acting in a similar way. As it turns out, he and his 'techie' friend has installed the motherboard directly onto the motherboard tray without using standoffs. Needless to say, he had to get a new motherboard - and use standoffs during the rebuild.

OK. Here's what I would do ...

You need to find a known good PSU of adequate capacity just to remove the possibility of a flaky PSU. I think your OS installation is OK. A corrupt OS installation will usually cause a hang at the the same place while booting.

Take the system completely apart, inspect, and carefully reassemble. Make sure the HSF is installed properly. Leave out the wi-fi card and tv tuner.

Boot and see what happens. Go into the BIOS and enable the extensive or long POST. That checks memory somewhat better. If you are OC'ing, go back to stock speeds.

If the computer is working, remove the wifi and tuner drivers. Then run memtest overnight. Then run orthos or prime95 with all 4 cores loaded for 12 hours to check for stability and memory operation. That will also show you worst case temperatures. If all that works, your memory is probably OK. OCZ and Patriot are reputable brands, but EVERYTHING seems to work with Crucial. I have been a Crucial fan for about 10 years.

If everything works for a week, get the latest drivers for the wi-fi and tuner cards. Install the wi-fi card and its driver. If it works for a week, install the tuner card.

If the PC doesn't work reliably after reassembling without the wifi and tuner cards, try installing XP instead to see what happens.

If you are certain the PSU is OK, RMA the motherboard.

Don't feel too bad. An almost working system can be much harder to troubleshoot than a simply dead system.

I would like to second jsc's suggestion but I would do this barebones rebuild outside of the case at first to take a case floor/mobo short or a fan short out of the equation and also take a faulty power or reset switch out of the equation.

This is odd. Vista is not crashing or just cutting off, something is attempting to shut it down, hence the message from your recording software and the option to keep going. This could be a power switch issue. On my ASUS mobo and Vista install if I press the power button I get the same thing, a quick but controlled shutdown of the OS, no sudden power off, although I'm not sure if I would get any warnings.

In any event this is worth checking for. If the case power button is malfunctioning that might, maybe, explain the other symptoms too.

The way you start a PC without a power button is to manually short the two pins on the mobo that the case power switch connects to. Just pop off the wire from the power switch to the jumper block and then put a screwdriver across the same 2 pins for a moment.

Whatever is causing this a barebones, outside case rebuild is in order at this point. See if the system will crash under those simple circumstances if so then we know it's basic hardware.

OK thanks for the first blast of advice. I'll get to it asap. Just to add a couple more diag data points. The replacement PSU I got was a Seasonic S12, really nice piece of PSU, I wanted to be sure. But as I said, it did exactly the same on first boot and a few more tries. I since then re-installed my original PSU, which I think is working fine, and I'll return the Seasonic (it was $150 at Fry's).
I've also restored back to before my Norton and Crysis install, and I seem to have regained some stability (but not the reliability I'd want). So this points me again towards a software issue.

Lorsus, I feel a bit stupid, but what are the 'stand-offs' you're talking about re mounting the motherboard on the tray? There was nothing with the case of the mobo that looked like it had to be inserted between the mobo and the aluminium tray, so I've screwed the mobo direct onto it. Are you talking about plastic pieces of some sort (don't seem to have that).

JSC, I suppose I can download these test routines from the web? Another stupid question (sorry guys) is, how do I stop the POST messages, they flash too fast, all seems OK in the glimpse I get.

Finally, I'm surprised I can't get sense out the Vista log and diags. Can anyone point me to where I should be looking? It mentiosn my shut downs but not the cause of them. I did find 2 suggestions in the performance and repair section of Control Panel, it suggests I update an ASUS utility ATX0110 ACPI, as well as a Intel ICH9. Do you guys think this could have anything to do with the problem?

The MOBO does not screw down to the case floor directly. If any part of the MOBO comes in contact with the metal floor this will cause a short. So the MOBO screws down on to some threaded risers/standoffs which you first screw into the mobo floor. On some cases these standoffs are already installed. Does ant of that ring a bell?

Have you checked the front panel? A system locking up won't ask to shut down, it'll just bomb out. If I'm reading this correctly it sounds like a problem with the power panel, power panel wiring, or MB power control. Sometimes **** bezels will push reset or power buttons, or you could have a couple of wires switched on the power panel wiring, or there is a prob with the MB. Also, look for loose screws in the case touching the MB, if they hit the right contact and the chassis they can cause voltage drop that could cause a power down.

To troubleshoot first inspect for bent components hitting bezel, recheck all the wires coming off the power panel, try disconnecting the power panel while it is running and see if it stops shutting down. If it's still shutting down then replace MB, as that's about the last component that could cause sporadic shutdowns, especially 'soft' shutdowns where it warns you first.

Yes, I wondered about this too and suggested this a post or two back. Did you see this JMF1?

If there isn't better than a 1/4" gap between the MB and the sheet metal behind it then you're missing these standoffs, usually brass or plastic. That will definitely cause a short.

OK guys; false alarm on the stand-offs, yes of course they were already mounted on the tray, elevating the mobo above the metal tray.

I'm interested in the power button hypothesis, but somehow, I feel this is not the problem. I've double checked the pins and it's connected OK, but the reason why I suspect this is not it, is because since I've restored to before Norton and Crysis, the PC has been running OK (for the last 3 hours) and I could not get it to stay on for 10 mins yesterday. Might be pure coincidence, but it sounds more like a deep software/bios/driver issue to me.

If you have tested a good PS and nothing, than it is the motherboard. Memory or Proc problems will usually lead to a BSOD or freezing. This sounds like a power issue. Definitely check that you mounted the board in the case on the standoffs. In not, there is your problem, hopefully you can still get some use out of it...